Camera: Set default thumbnail size with matched aspect ratio

Make default thumbnail size match the default still capture size aspect ratio.

Bug: 10885012
Change-Id: If46da9508d3b71992f0e14a35c600b7e8d347f4e

2 files changed, 41 insertions, 3 deletions

diff --git a/services/camera/libcameraservice/api1/client2/Parameters.cpp b/services/camera/libcameraservice/api1/client2/Parameters.cpp
index a6c1083..8e197a9 100644
--- a/services/camera/libcameraservice/api1/client2/Parameters.cpp
+++ b/services/camera/libcameraservice/api1/client2/Parameters.cpp
@@ -250,9 +250,17 @@ status_t Parameters::initialize(const CameraMetadata *info) {
         staticInfo(ANDROID_JPEG_AVAILABLE_THUMBNAIL_SIZES, 4);
     if (!availableJpegThumbnailSizes.count) return NO_INIT;
 
-    // TODO: Pick default thumbnail size sensibly
-    jpegThumbSize[0] = availableJpegThumbnailSizes.data.i32[0];
-    jpegThumbSize[1] = availableJpegThumbnailSizes.data.i32[1];
+    // Pick the largest thumbnail size that matches still image aspect ratio.
+    ALOG_ASSERT(pictureWidth > 0 && pictureHeight > 0,
+            "Invalid picture size, %d x %d", pictureWidth, pictureHeight);
+    float picAspectRatio = static_cast<float>(pictureWidth) / pictureHeight;
+    Size thumbnailSize =
+            getMaxSizeForRatio(
+                    picAspectRatio,
+                    &availableJpegThumbnailSizes.data.i32[0],
+                    availableJpegThumbnailSizes.count);
+    jpegThumbSize[0] = thumbnailSize.width;
+    jpegThumbSize[1] = thumbnailSize.height;
 
     params.set(CameraParameters::KEY_JPEG_THUMBNAIL_WIDTH,
             jpegThumbSize[0]);
@@ -2525,6 +2533,32 @@ status_t Parameters::getFilteredPreviewSizes(Size limit, Vector<Size> *sizes) {
     return OK;
 }
 
+Parameters::Size Parameters::getMaxSizeForRatio(
+        float ratio, const int32_t* sizeArray, size_t count) {
+    ALOG_ASSERT(sizeArray != NULL, "size array shouldn't be NULL");
+    ALOG_ASSERT(count >= 2 && count % 2 == 0, "count must be a positive even number");
+
+    Size maxSize = {0, 0};
+    for (size_t i = 0; i < count; i += 2) {
+        if (sizeArray[i] > 0 && sizeArray[i+1] > 0) {
+            float curRatio = static_cast<float>(sizeArray[i]) / sizeArray[i+1];
+            if (fabs(curRatio - ratio) < ASPECT_RATIO_TOLERANCE && maxSize.width < sizeArray[i]) {
+                maxSize.width = sizeArray[i];
+                maxSize.height = sizeArray[i+1];
+            }
+        }
+    }
+
+    if (maxSize.width == 0 || maxSize.height == 0) {
+        maxSize.width = sizeArray[0];
+        maxSize.height = sizeArray[1];
+        ALOGW("Unable to find the size to match the given aspect ratio %f."
+                "Fall back to %d x %d", ratio, maxSize.width, maxSize.height);
+    }
+
+    return maxSize;
+}
+
 Parameters::CropRegion Parameters::calculateCropRegion(
                             Parameters::CropRegion::Outputs outputs) const {
 
diff --git a/services/camera/libcameraservice/api1/client2/Parameters.h b/services/camera/libcameraservice/api1/client2/Parameters.h
index 0505b0e..2e78c73 100644
--- a/services/camera/libcameraservice/api1/client2/Parameters.h
+++ b/services/camera/libcameraservice/api1/client2/Parameters.h
@@ -168,6 +168,8 @@ struct Parameters {
     // Max preview size allowed
     static const unsigned int MAX_PREVIEW_WIDTH = 1920;
     static const unsigned int MAX_PREVIEW_HEIGHT = 1080;
+    // Aspect ratio tolerance
+    static const float ASPECT_RATIO_TOLERANCE = 0.001;
 
     // Full static camera info, object owned by someone else, such as
     // Camera2Device.
@@ -331,6 +333,8 @@ private:
     Vector<Size> availablePreviewSizes;
     // Get size list (that are no larger than limit) from static metadata.
     status_t getFilteredPreviewSizes(Size limit, Vector<Size> *sizes);
+    // Get max size (from the size array) that matches the given aspect ratio.
+    Size getMaxSizeForRatio(float ratio, const int32_t* sizeArray, size_t count);
 };
 
 // This class encapsulates the Parameters class so that it can only be accessed